1. Field of the Invention
The present invention relates to a measuring device for measuring a distance of an object to be photographed from a camera with which it is being photographed. More precisely, it relates to an object distance measuring device in a camera having an active autofocusing system with an infrared LED which emits light for measuring the distance of the object to be photographed.
2. Description of the Related Art
In a camera having an active autofocusing system with an infrared LED, an infrared light for measuring distance is emitted toward the object from the infrared LED provided in the camera body. This measuring light is then reflected by the object and received by a light receiver on the camera body, which detects the object distance in accordance with the measuring light. Based on the object distance thus obtained, a focusing lens of a photographing lens of the camera is moved to a focus position.
Upon taking a picture using such an autofocusing camera, a photographer must adjust a distance measuring zone located at the center of the field of view of a finder to be coincident with the object to be photographed. Thereafter, the photographer first pushes the release switch down a half step to focus the focusing lens, and then fully pushes the release switch down the full step to expose the film at the fixed camera angle. If a photographer wants to take a picture while making the focus point coincident with a portion of the field of view of a finder other than the center thereof, he or she must first adjust the object distance measuring zone located at the center of the field of view of a finder to be coincident with an object. The photographer then pushes the release switch down by a half step to lock the focus, and then change the camera angle to obtain a desired composition of the picture in the finder. When the desired composition is obtained, the release switch is pushed down by the full step to effect the exposure.
However, it is very difficult, particularly for a beginner, to move the camera to the desired position while pushing the release switch by a half step. Furthermore, if the release switch, which has been pushed down by a half step, is accidentally returned to the initial position during the movement of the camera, the focus lock is released, so that the object distance measuring must be effected again from the beginning, which is very troublesome.